Low power and Lossy Networks (LLNs), e.g., sensor networks, have a myriad of applications, such as Smart Grid and Smart Cities. Various challenges are presented with LLNs, such as lossy links, low bandwidth, battery operation, low memory and/or low processing capability of nodes. One example routing solution to LLN challenges is a protocol called Routing Protocol for LLNs or “RPL,” which is a distance vector routing protocol. One or more instances of the RPL protocol can be used to build a routing topology that is deployed over the LLN using a set of metrics and constraints. Each RPL routing topology built by an RPL instance may be represented by a Directed Acyclic Graph (DAG) that is rooted by a root node. Other nodes of the LLN may participate in the routing topology by discovering and attaching to the DAG based on configuration and policies.
The root node of the DAG is a central authority that manages and controls several critical routing parameters used by the nodes participating in the RPL topology. Furthermore because of the DAG structure, a substantial amount of traffic in the routing topology tends to be concentrated around the DAG root node. A software upgrade or change in operational mode of the DAG root node may result in a failure (i.e., unavailability) and subsequent reboot (via a reboot process) of the root node. In response to detecting that the DAG root node is unavailable, the other nodes may attempt (re-) convergence in the routing topology by, e.g., attaching to another root node, thereby possibly leading to collapse of the DAG. Consequently, a reboot of the DAG root node may have adverse consequences on network stability.